1. Field of the Invention
The present invention relates to a method of modifying carbon nanotubes using a radical initiator, and a dispersion liquid and an electrode comprising the carbon nanotube modified by using the method, and more particularly, to a method of modifying a surface of a carbon nanotube by reacting a radical initiator with the carbon nanotube, wherein the radical has reacted with the carbon nanotube is detached from the carbon nanotube after the reaction with the carbon nanotube, and a dispersion liquid and an electrode comprising the carbon nanotube modified by using the method.
2. Description of the Related Art
Carbon nanotubes (CNTs) are carbon structures in which carbon atoms are arranged in a hexagonal and honeycomb-like structure, thus taking the form of tubes. CNTs are very anisotropic, and have various structures such as a single wall structure, a multi-wall structure, a structure including bundles, and the like. CNTs are nanometer-scale structures having nanometer-scale diameters (nm=1 to 1 billion meter). CNTs have excellent mechanical properties, high electrical selectivity, excellent field emission properties, highly efficient hydrogen storage medium properties, and the like.
In addition, CNTs behave like semiconductors or metals according to the pattern in which carbon atoms are arranged in the hexagonal and honeycomb-like structure. An energy gap depends on the diameter of each CNT, and CNTs have quasi-one dimensional electronic structure so that they have particular quantum properties.
Examples of methods of preparing CNTs include arc discharge, pyrolysis, laser deposition, plasma enhanced chemical vapor deposition (PECVD), thermal chemical vapor deposition, electrolysis, and the like.
CNTs have high electrical conductivity, thus are used in the formation of a conductive layer, and the like. In addition, in the future, there is high possibility of the use of CNTs in a variety of functional complexes such as a probe, and the like of field emission displays (FEDs) and scanning probe microscopes (SPMs). Therefore, research on such uses of CNTs has been actively conducted.
CNTs prepared by the conventional method are mixtures of metallic CNT and semiconducting CNT, and property of the CNTs depends on their structures and optical chiralities. However, to be used as an electrode material, or the like, CNTs have to have increased conductivity. Therefore, methods of separating only CNTs having metallic properties, increasing an amount of CNTs having metallic properties in CNTs, or the like are required.
As an example of such a method, U.S. Patent Publication No. 20060045838 discloses a method of separating metallic CNTs and non-metallic CNTs using a dispersant.
However, this method using separation has problems in that the separation is not completely successful, and the separation procedures are complicated.
Accordingly, to address those problems in the art, a method of simply modifying a surface of a carbon nanotube is required.